<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    /*等腰梯形*/
    .trapezoidal{
      /*主体横向宽度 不算梯形两边的宽度*/
      width: 126px;
      height:0;
      /*梯形的高度(用border撑起来的)*/
      border-bottom: 39px solid black;
      /*两边的宽度*/
      border-right: 17px solid transparent;
      border-left: 17px solid transparent;
    }
  </style>
</head>
<body>
<div class="trapezoidal"></div>
</body>
</html>
